The major objective of the proposed research in the immediate future are two-fold: 1) Isolation, characterization and biosynthesis of glycosphingolipids of the globoside family in guinea pig embryonic 103 cells and their chemically transformed variant 104Cl cell. Differential binding of 125I-labeled lectins (Dolichos biflorus and Bandeiraea simplicifolia) and toxins (cholera and ricin) to 103, 104Cl and 106B cell surfaces under various growth conditions. 2) Studies on the structure and biosynthesis of N-acetylglucosamine containing blood-group related neutral glycosphingolipids in mouse neuroblastoma N-18 and human neuroblastoma IMR-32 cells. Differential binding of 125I-labeled lectins (Ulex europeus, Euonymus europeus and Lotus tetragonolobus), cholera toxin, and ricin to IMR-32 and N-18 cell surface before and after chemically induced (6-MG, BrdUrd and (But)2cAMP) differentiation. The glycosphingolipids are highly enriched in the plasma membranes of eukaryotic cells. Alterations in their composition and modification of their glycose units might affect intercellular relationship. Our preliminary observations and the proposed studies should provide insight into the cell-surface glycosphingolipid alterations during chemical transformation of an embryonic cell line (103 vs 104Cl) and during chemically induced differentiation of tumor cells (N-18 and IMR-32). Furthermore, we hope to compare the structures of glycosphingolipids present on the surfaces of tumor cells of two different species (mouse N-18 vs. human IMR-32).